diff --git a/config.mk b/config.mk
index b1476d2e..64ec76c5 100644
--- a/config.mk
+++ b/config.mk
@@ -124,7 +124,7 @@ else
 endif
 
 LIB_CFLAGS:=${CFLAGS} ${CPPFLAGS} -I. -I.. -I../lib -std=c99
-LIB_CXXFLAGS:=$(LIB_CFLAGS) ${CPPFLAGS}
+LIB_CXXFLAGS:=$(CFLAGS) ${CPPFLAGS} -I. -I.. -I../lib
 LIB_LDFLAGS:=${LDFLAGS}
 
 BROKER_CFLAGS:=${LIB_CFLAGS} ${CPPFLAGS} -DVERSION="\"${VERSION}\"" -DWITH_BROKER -std=c99